Free web app Keybr.com is a simple touch type practice tool that shows you how fast and error-free your typing is through an escalating series of exercises. Like a web-based version of previously mentioned Windows-only tools TypeFaster and RapidTyping, Keybr.com could help you make the switch to a Dvorak layout, or learn to switch from a U.S. to UK, Spanish, German, or Russian keyboard (or vice-versa). Keybr.com is free to use and doesn't require a sign-up.